/*
    This file is part of the substandard lisp implementation of Standard Lisp
    Copyright (C) 2011 Nicky Nickell

    substandard lisp is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

function std_eqn(a, env) {
  var u = a[0];
  var v = a[1];

  if (u == v) {
    return T;
  }

  if (type_check(u.type, CLASS_NUMBER) && type_check(v.type, CLASS_NUMBER)) {
    if (u.type == TYPE_INTEGER && v.type == TYPE_INTEGER) {
      return (u.value.compare(v.value) == 0) ? T : NIL;
    } else if (u.type == TYPE_FLOATING && v.type == TYPE_FLOATING) {
      return (v.value == u.value) ? T : NIL;
    } else {
      return NIL;
    }
  } else {
    return NIL;
  }
}

/*---
name: eqn
arity: 2
rest: false
ftype: FTYPE_EXPR

synonyms:
  - '='

argument-types:
  - CLASS_ANY
  - CLASS_ANY

doc: |
  explaining what eqn is / how it is used!

tests: |
  (eqn 'a 'b) -> NIL
  (eqn 'a 'a) -> T
  (eqn NIL T) -> NIL
  (eqn T T) -> T
  (eqn 1 T) -> NIL
  (eqn 1 1) -> T
  (eqn 1 2) -> NIL
  (eqn 1.0 1.0) -> T
  (eqn 1.0 2.0) -> NIL
  (eqn 1 2.0) -> NIL
...*/
